This paper reports on aspects of land tenure in western Sudan, especially the nature of tenure insecurity and the functioning of the land rental market. The active land rental market accounted for about one-third of cultivated land. Patterns of land rental transactions, and tests of the importance of insecurity in renting land, where the owner may not be able to reclaim land rented out, do not support the presumption that rental markets perform poorly. The role of the sheikh as administrator of village land, and the claims of large landowners to vast tracts, are, however, important political problems that must be resolved before attempts at "rationalizing" land tenure.